feat: run on_http_response_headers (#30)

Author: spacewander

README.md

@@ -83,6 +83,26 @@ end
 assert(wasm.on_http_request_headers(ctx))
 ```
 
+### on_http_reponse_headers
+
+`syntax: ok, err = proxy_wasm.on_http_reponse_headers(plugin_ctx)`
+
+Run the HTTP response headers filter in the plugin of the given plugin ctx.
+
+```lua
+local plugin, err = proxy_wasm.load("plugin","t/testdata/http_lifecycle/main.go.wasm")
+if not plugin then
+    ngx.log(ngx.ERR, "failed to load wasm ", err)
+    return
+end
+local ctx, err = wasm.on_configure(plugin, '{"body":512}')
+if not ctx then
+    ngx.log(ngx.ERR, "failed to create plugin ctx ", err)
+    return
+end
+assert(wasm.on_http_response_headers(ctx))
+```
+
 ## proxy-wasm ABI
 
 Implemented proxy-wasm ABI can be found in [proxy_wasm_abi](./proxy_wasm_abi.md).

lib/resty/proxy-wasm.lua

@@ -28,6 +28,9 @@ ngx_str_t *ngx_http_wasm_fetch_local_body(void *r);
 
 local _M = {}
 local HTTP_REQUEST_HEADERS = 1
+--local HTTP_REQUEST_BODY = 2
+local HTTP_RESPONSE_HEADERS = 4
+--local HTTP_RESPONSE_BODY = 8
 
 
 function _M.load(name, path)
@@ -100,4 +103,23 @@ function _M.on_http_request_headers(plugin_ctx)
 end
 
 
+function _M.on_http_response_headers(plugin_ctx)
+    if type(plugin_ctx) ~= "cdata" then
+        return nil, "bad plugin ctx"
+    end
+
+    local r = get_request()
+    if not r then
+        return nil, "bad request"
+    end
+
+    local rc = C.ngx_http_wasm_on_http(plugin_ctx, r, HTTP_RESPONSE_HEADERS)
+    if rc < 0 then
+        return nil, "failed to run proxy_on_http_response_headers"
+    end
+
+    return true
+end
+
+
 return _M

proxy_wasm_abi.md

@@ -104,6 +104,20 @@ Called when HTTP request headers are received from the client. TODO: Headers can
 
 TODO: pass a correct `num_headers` but not 0.
 
+### `proxy_on_response_headers`
+
+* params:
+  - `i32 (uint32_t) context_id`
+  - `i32 (size_t) num_headers`
+  - `i32 (bool) end_of_stream`
+* returns:
+  - `i32 (proxy_action_t) next_action`
+
+Called when HTTP response headers are received from the upstream. TODO: Headers can be retrieved using
+`proxy_get_map` and/or `proxy_get_map_value`.
+
+TODO: pass a correct `num_headers` but not 0.
+
 
 # Functions implemented in the host environment
 

src/http/ngx_http_wasm_module.c

@@ -30,10 +30,15 @@ static ngx_str_t proxy_on_done = ngx_string("proxy_on_done");
 static ngx_str_t proxy_on_delete = ngx_string("proxy_on_delete");
 static ngx_str_t proxy_on_request_headers =
     ngx_string("proxy_on_request_headers");
+static ngx_str_t proxy_on_response_headers =
+    ngx_string("proxy_on_response_headers");
 
 
 typedef enum {
     HTTP_REQUEST_HEADERS = 1,
+    HTTP_REQUEST_BODY = 2,
+    HTTP_RESPONSE_HEADERS = 4,
+    HTTP_RESPONSE_BODY = 8,
 } ngx_http_wasm_phase_t;
 
 
@@ -594,6 +599,7 @@ ngx_http_wasm_on_http(ngx_http_wasm_plugin_ctx_t *hwp_ctx, ngx_http_request_t *r
 {
     ngx_int_t                        rc;
     ngx_log_t                       *log;
+    ngx_str_t                       *cb_name;
     ngx_http_wasm_http_ctx_t        *http_ctx;
     ngx_http_wasm_main_conf_t       *wmcf;
 
@@ -614,13 +620,20 @@ ngx_http_wasm_on_http(ngx_http_wasm_plugin_ctx_t *hwp_ctx, ngx_http_request_t *r
         return NGX_DECLINED;
     }
 
+
+    if (type == HTTP_RESPONSE_HEADERS) {
+        cb_name = &proxy_on_response_headers;
+    } else {
+        cb_name = &proxy_on_request_headers;
+    }
+
     if (hwp_ctx->hw_plugin->abi_version == PROXY_WASM_ABI_VER_010) {
         rc = ngx_wasm_vm.call(hwp_ctx->hw_plugin->plugin,
-                              &proxy_on_request_headers,
+                              cb_name,
                               true, NGX_WASM_PARAM_I32_I32, http_ctx->id, 0);
     } else {
         rc = ngx_wasm_vm.call(hwp_ctx->hw_plugin->plugin,
-                              &proxy_on_request_headers,
+                              cb_name,
                               true, NGX_WASM_PARAM_I32_I32_I32, http_ctx->id,
                               0, 1);
     }

t/http_lifecycle.t

@@ -105,10 +105,10 @@ location /t {
     }
 }
 --- grep_error_log eval
-qr/run http ctx \d+ with conf \S+/
+qr/run http ctx \d+ with conf \S+ on http request headers,/
 --- grep_error_log_out
-run http ctx 3 with conf {"body":512},
-run http ctx 4 with conf {"body":256},
+run http ctx 3 with conf {"body":512} on http request headers,
+run http ctx 4 with conf {"body":256} on http request headers,
 
 
 
@@ -126,7 +126,53 @@ location /t {
     }
 }
 --- grep_error_log eval
-qr/run http ctx \d+ with conf \S+/
+qr/run http ctx \d+ with conf \S+ on http request headers,/
 --- grep_error_log_out
-run http ctx 2 with conf {"body":512},
-run http ctx 2 with conf {"body":256},
+run http ctx 2 with conf {"body":512} on http request headers,
+run http ctx 2 with conf {"body":256} on http request headers,
+
+
+
+=== TEST 6: on reponse headers
+--- config
+location /t {
+    content_by_lua_block {
+        local wasm = require("resty.proxy-wasm")
+        local plugin = assert(wasm.load("plugin", "t/testdata/http_lifecycle/main.go.wasm"))
+        local ctx = assert(wasm.on_configure(plugin, '{"body":512}'))
+        ngx.ctx.ctx = ctx
+        assert(wasm.on_http_request_headers(ctx))
+    }
+    header_filter_by_lua_block {
+        local wasm = require("resty.proxy-wasm")
+        local ctx = ngx.ctx.ctx
+        assert(wasm.on_http_response_headers(ctx))
+    }
+}
+--- grep_error_log eval
+qr/run http ctx \d+ with conf \S+ on [^,]+,/
+--- grep_error_log_out
+run http ctx 2 with conf {"body":512} on http request headers,
+run http ctx 2 with conf {"body":512} on http response headers,
+
+
+
+=== TEST 7: crash on reponse headers
+--- config
+location /t {
+    content_by_lua_block {
+        local wasm = require("resty.proxy-wasm")
+        local plugin = assert(wasm.load("plugin", "t/testdata/http_lifecycle/main.go.wasm"))
+        ngx.ctx.plugin = plugin
+    }
+    header_filter_by_lua_block {
+        local wasm = require("resty.proxy-wasm")
+        local plugin = ngx.ctx.plugin
+        local ctx = assert(wasm.on_configure(plugin, 'panic_on_http_response_headers'))
+        local ok, err = wasm.on_http_response_headers(ctx)
+        ngx.log(ngx.ERR, err)
+    }
+}
+--- error_log
+failed to call function
+failed to run proxy_on_http_response_headers

t/testdata/http_lifecycle/main.go

@@ -45,6 +45,25 @@ func (ctx *httpLifecycle) OnHttpRequestHeaders(numHeaders int, endOfStream bool)
 		return types.ActionContinue
 	}
 
-	proxywasm.LogWarnf("run http ctx %d with conf %s", ctx.contextID, string(data))
+	proxywasm.LogWarnf("run http ctx %d with conf %s on http request headers",
+		ctx.contextID, string(data))
+	return types.ActionContinue
+}
+
+func (ctx *httpLifecycle) OnHttpResponseHeaders(numHeaders int, endOfStream bool) types.Action {
+	data, err := proxywasm.GetPluginConfiguration()
+	if err != nil {
+		proxywasm.LogCriticalf("error reading plugin configuration: %v", err)
+		return types.ActionContinue
+	}
+
+	action := string(data)
+
+	if action == "panic_on_http_response_headers" {
+		panic("OUCH")
+	}
+
+	proxywasm.LogWarnf("run http ctx %d with conf %s on http response headers",
+		ctx.contextID, string(data))
 	return types.ActionContinue
 }